Thermal responsive device and method of calibration therefor



Sept. 17, 1957 c. w. WOOD 2,305,375

THERMAL RESPONSIVE DEVICE AND METHOD OF CALIBRATION THEREFOR Filed larch 5, 1954 INVENTOR. CHARLES W. WOOU v-ns ATTORNEYS United States THERMAL RESPGNSIVE DEVICE AND METHOD OF CALIBRATEON THEREFOR Application March 3, 1954, Serial No. 413,787

4 Claims. ((ll. 73368.3)

This invention relates to a thermal responsive device and a method of calibration therefor. The invention relates particularly to a thermal responsive device for controlling and/ or indicating temperatures. The invention relates more particularly to my application, Serial No. 333,707, filed on or about January 28, 1953.

This invention relates to a type of thermal responsive device in which a movable element or actuator is partially disposed within a container, which container also contains an expansible-contractible material such as disclosed in the aforementioned application, Serial No. 333,707.

In a thermal responsive device, such as disclosed in the aforementioned application, the expansible-contractible material encircles or surrounds the actuator and receives an indication of the surrounding temperature through the walls of the container. When the expansible-contractible material receives heat through the walls of the container, this heat causes the expansible-contractible material to expand. Every portion of the expansible-contractible material which is heated expands.

1f suflicient expansion occurs, an actuator partially disposed within the container is forced to move outwardly from within the container as a result of the volumetric expansion of the expansible material within the container. In former devices, only a portion of the expansive material was readily heated as a result of conduction through the walls of the container. This was due to the fact that a large portion of the mass of the expansive material was disposed inwardly within the container and did not contact the wall surface or was not adjacent a wall surface. The result was that the volumetric expansion of the expansive material was not so great as if all of the expansive material were heated. In order for a thermal device of this type to be readily responsive and accurate, each portion of the expansive material within the container should quickly be heated when temperature increases and each portion should expand to increase the total volumetric expansion within the container.

Furthermore, in order that the operation of the actuator within the container be accurate, the movement of the actuator must always be the same in response to a given temperature.

Hence, an object of this invention is to provide a thermal responsive device in which the operation of said device is accurate and responds readily to all changes in the temperature of the ambient.

Another object of the invention is to provide a method of calibration of such a thermal responsive device by changing the shape of the body portion of the device, which method may be easily and efficiently performed.

Another object of the invention is to provide a method of calibration, which method provides a container through which an indication of the surrounding temperature is accurately and swiftly transmitted by conduction through the walls thereof to the expansible material therein.

Another object of the invention is to provide a thermal device of the type disclosed above, the container of which is provided with efiective means for sealing the movable atent ice actuator to prohibit any leakage of liquid into the con-- tainer through the aperture which receives the actuator. Other objects and advantages reside in the construction of parts, the combination thereof and the mode of operation, as will become more apparent from the following.

description.

In the drawing,

Figure 1 is a side sectional view of the thermal responsive device of this invention before the calibration thereof.

Figure 2 is a side elevational view of the thermal responsive device of this invention after the calibration thereof.

Figure 3 is a sectional view taken substantially on line 3-3 of Figure 2.

Figure 4 is a sectional View taken substantially on line 44 of Figure 3.

Figure 5 is a fragmentary side elevational exploded view disclosing the elements of the thermal responsive device during assembly thereof.

Figure 6 is a sectional view, similar to that of Figure 3, disclosing a modification in the body structure or container structure as a result of the calibration of the thermal responsive device.

Referring to the drawing in detail, the main body portion of the thermal responsive device of this invention comprises a container 10. Within the container 10 is disposed an elastic spool 12 which has a longitudinal bore 14, extending a portion of the length of the spool 12. The spool 12 is provided at one end thereof with a flange 16. The flange 16 may be adhesively attached to a disc cover 20 for increasing the ease of assembly, or the spool may be inserted within the container 10 without attachment of the flange 16 to the disc cover 20. A sealing collar 21 is adhesively attached to the outer side of the disc cover 24 The container 10 is partially filled with an expansible-contractible material 24, such as disclosed in the aforesaid application. Air is then removed from the container 10. Following this the spool 12 is inserted into the container 10 so that the spool 12 engages the floor of the container and the expansive material 24 is retained between the container 10 and the spool 12 as shown in Figure 1. An upper end 26 of the container 10 is bent inwardly, as shown in Figures 1 and 4, holding the cover 20 within the container 10. The peripheral flange 16 is formed at an angle greater than 45 degrees, as shown in Figure 5. The flange 16 has an annular groove 28 adjacent its angular periphery and concentric therewith. The container 10 is provided with an annular inclined portion 30 adjacent the end 26. The inclined portion 3t) is approximately 45 degrees with respect to the other portions of the container 10. Thus, the periphery of the flange 16 is pushed inwardly by the inclined portion 30 when the spool is assembled within the container 10, as best shown in Figure 1. The disc cover 20 is firmly held against the flange 16 of the spool 12 by means of the inwardly bent upper portions 26 of the container 10. The cover 20 bears upon the flange 1 6 and the inclined periphery of the flange 16 presses against inclined portions 30 at the upper end of the container 10, thus providing effective sealing means within the container 10.

The sealing collar 21 on the outer side of the cover 20 has an aperture 32 therethrough. The aperture 32 is tapered, thus having a larger opening at one end than at the other end, as best shown in Figure 5.

A portion of an actuator 34 having a tapered end 36 is positioned within the longitudinal bore of the spool 12, as shown in Figures 1 and 4. As best shown in Figure 5, the diameter of the body of the actuator 34 is larger than the diameter of the smaller opening of the aperture 32 of the collar 21 so that when the actuator 34 is positioned within the body portion of the spool 12', throughthe aperture'32' of the sealing collar 21, the upper'side of the collar 21"snugly seals around theactuator 34. This sealing collar 21 thereby effectively seals around the body of .the actuator 34 so that fluid may not flow downwardly through'the'cover 20 and intothe longitudinal bore'14of'the. spool 1Z5 Afterthe elements of the thermal responsive device are assembled; as shown inFigure 1, the thermal responsive deviceis then'calibrated so that'the actuator 34'will accurately respond to changes in temperature.

The calibration of the thermal expansive elementis 'as follows: the thermal responsive device is placed into a fluid, the temperature of which is maintained at a constantvalue; for example, at 160 Fahrenheit. While the device is: so submerged, a plurality of' portions of' the side walls'of the container""'areforcedinwardly and depressed by any suitable means causing depressions 38. Thecontainer 10" then' assumes a general appearance,

such as shown in Figures 2, 3 and 4. The side walls are thus pushed inwardly until such inward movement of the side walls of the container 10 causes the'expansive material24 tocompletely fill the space within the container between the side wallsof' the container and the elastic spool, as shown in Figure 4, so that movement oftheactuator 34-results. At the instant atwhich-the actuator 34 begins to move from the container 10, the

calibrating'pressure upon the side walls is immediately tion of this thermal devicetheactuator 34-willalways begin to move'outwardly from within the container 10 upon each-occasion in which the ambient temperature reaches 160". This iscalledthe operating point of the thermal device.

Upon furtherrise in the" temperature, the actuator 34 moves outwardly from within the container 10 a-further distance,- depending upon" the temperature. This is a resultof the expansion of the expansive-material 24 within the container 10, which forces the bodyof the spool 12' inwardly. This volumetric expansion" of the expan sive material 24 is always the same fora'given'temperw ture of the expansivematerial24. Also, the actuator returns to a predetermined position whenever the ambient temperature decreases. Therefore, on each occasion when the temperature of' the expansive materialreaches 160 or higher, the actuator 34 moves outwardly'from within the container forced by the'pressure of the expansive material upon the elastic spool 12.

Due tothe inward position of the'depressions 38', as shown in- Figures 2, 3 and 4, most ofthe expansive-material 24' directly contacts or is' closely adjacent the'enclosing walls of the container 10: Thus, ahigh rate ofiheat transfer from the exterior of the container 10to the entire body of expansive material 24' ispossible. Thus, due to the fact that the depressions38cause most of the expansive material 24-to bedirectly'subjected'to the temperature conditions of the fluid within which the thermalresponsive device-is located, all of the'expansive material 24 within the container 10 quickly receives an indication of anychange in ambient temperature. Hence, accurate and rapid response results; The calibration of the thermal responsive device positions all of the expansivematerial' 2'4'within the container 19," adjacent the enclosing walls thereof, while at the same time, establishing the operating point of the device.

Figure 6 is a sectional view similarv to that of Figure 3,.showing a larger number of portions of the enclosing walls of the container 10 pressed inwardly. A container 40, similar to container 10 hasa plurality of depressions 42' as a result of the calibration process. The greater number of depressions causes the expansive material 24 to have a greater portion thereof directly in contact with the enclosing walls of the container or closely adjacent to the enclosing walls.

The outer end of the actuator 34 is provided with a threaded portion 44 for attachment to any suitable device for indication and/or control of temperature.

It is to be understood that the Fahrenheit, or the operating temperature, chosen as an example for the calibration-of the thermal responsive device as discussed above, is only one temperature at which the thermal responsive device may be calibrated. Temperatures of a greater value or of a lesser value than 160 Fahrenheit might be used, depending upon the purpose for which the thermal responsive device is used.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. The method of adjusting a thermal responsive device for operationat a given temperature, the thermal responsive device including a container having enclosing walls consisting of side walls and end walls, an elastic body within'the'container, an actuator extending into the container and into the elastic body, and an expansiblecontractible non-compressiblematerial within the contamer-filling aportionof the space between the enclosing walls and the'elastic body, the method comprising the steps of submerging-the container within a fluid, the temperature of which is maintained at the aforesaid given temperature, followed by pressing inwardly upon a plurality of portions of the side walls of the container until the space between the enclosing walls and the elastic body is completely filled with the expansible-contractible material, thus causing the actuator to move outwardly from the container, the inwardly extending side walls also providing a comparatively large amount of surface area adjacent the expansible-contractible material.-

2. A thermal responsive device comprising a container, the container having an angularly diverging portion provided with an opening therein, a cover member closing the opening, a sealing member engaging the cover member and the diverging portion of the container, the sealing member having substantially parallel flat side portions, one of the side portions being in engagement with thecover member, the periphery of the sealing member being at an oblique angle with respect to the flat side portions thereof, the sealing member being provided with an annular groove within the side portion opposite the cover member and adjacent the periphery of the sealing member, the angle of the diverging portion of the container being less than the angle of the periphery of the sealing member thus causing bending and sealing'action of member thus applying pressure upon the periphery of the sealing member, pressing the periphery of the sealing member against the diverging portion of the container.

3. In a thermal device, the combination including a container provided with enclosing walls open at one end thereof, a spool-comprising an elastic material retained within the container, the spool having a body portion and a centrally located longitudinal hole therein, an expansive material within the container surrounding the body portion of the spool, a cover member enclosing the open end of the container, the cover member being provided with an aperture therein, the cover having a depressed tapered portion encompassing the aperture, a tapered sealing. collar attached to the cover member within the depressed portion, the sealing collar having an aperture therethrough, the aperture being tapered-and having a larger opening at one end thereof than at the other end thereof, the larger opening being positioned within the depressed portion of the cover member, and an actuator extending through the aperture in the sealing collar and through the aperture in the cover member and snugly positioned within the hole in the body of the spool.

4. A device comprising a container having rigid enclosing Walls, one of the enclosing walls having an aperture therethrough, an elongate elastic body within the container, the elastic body having an elongate bore therein open at one end of the body and extending a portion of the length thereof, the elastic body having a flange at the open end thereof, the open end of the bore being tapered outwardly, the enclosing wall of the container which has the aperture therethrough being provided with a tapered protuberance within the container and through which the aperture extends, the tapered protuberance fitting within the tapered open end of the bore of the elastic body, the flange of the elastic body being in engagement with the enclosing wall having the aperture therethrough, the container having diverging enclosing walls adjacent the enclosing wall which has the aperture therethrough, the diverging enclosing walls being substantially parallel to the tapered protuberance having the aperture therethrough, the flange of the elastic body having peripheral edge portions formed at an oblique angle, the angle of the diverging enclosing walls being ditferent from the angle of the peripheral edge portions of the flange, thus providing bending and sealing action of the flange as the peripheral edge portions thereof engage the diverging enclosing walls, the fiange being snugly disposed between the tapered protuberance and the diverging enclosing walls.

References Cited in the file of this patent UNITED STATES PATENTS 671,697 Hammon Apr. 9, 1901 699,199 Lockwood May 6, 1902 963,645 Pendleton July 5, 1910 1,009,303 Hansen Nov. 21, 1911 1,285,990 Halsey Nov. 26, 1918 1,348,589 Seeger Aug. 3, 1920 2,039,009 Lampman Apr. 28, 1936 2,274,234 Ekkebus Feb. 24, 1942 2,355,043 Adlam Aug. 8, 1944 2,453,851 Miller Nov. 16, 1948 2,507,466 De Craene May 9, 1950 2,714,759 Wangenheim Aug. 9, 1955 FOREIGN PATENTS 254,205 Switzerland Apr. 30, 1948 436,836 Great Britain Oct. 18, 1935 

